PESTS OF POTATO

Irish potatoes re attacked by most of the insects which infest closely related solanaceous plants
like tomato, eggplant, and pepper. However, since potatoes are grown for their edible tubers, they
must receive greater protection from soil-inhabiting pests. Wireworms, tuberworms, white grubs,
and vegetable weevils are pests for which growers should watch.

Aphids - Soft-bodied, pear-shaped insects with a pair of dark
cornicles and a cauda protruding from the abdomen; may be winged or wingless - wingless forms
most common; feed in colonies; cause discoloration or mottling of the foliage; often transmit virus
diseases; excrete honeydew on which sooty mold grows

B. Pests that feed on underground plant parts, bore into stems, or mine in leaves and petioles

European corn borer - Cream to light pink caterpillar with reddish-brown to
black head; body up to 26 mm long with several rows of dark spots; has 3 pairs of legs near head
and 5 pairs of prolegs (Fig. 177); bores into stem; tangled frass and silk near
entrance hole; stem may break, plant may yellow or wilt readily

Potato tuberworm - Creamy white (young) or green to pink (mature)
caterpillar up to 19 mm long with dark brown head; 3 pairs of legs near head and 5 pairs of
prolegs (Fig. 178); mines in older lower leaves causing grayish papery blotches;
tunnels in exposed tubers or those close to soil surface, filling tunnels with excrement; entrance
holes usually near the eyes and surrounded by a pink coloration

White grubs - Several species of creamy white grubs with a distinct brown
head capsule, three pairs of legs near the head, and slightly enlarged abdomen; body C-shaped and
up to 50 mm long (Fig. 180); sever roots and stems of potatoes; leave large,
shallow circular holes in tubers

Wireworms - Several species of slender, wire-like larvae with three pairs of
short legs near the head and a pair of prolegs at the tip of the abdomen; large shallow cavities in
sweet potatoes - evidence of early injury; deep ragged holes - later injury